It's just another name for isopropyl alcohol, or isopropanol. It's toxic in large amounts, like 200 mls, but fine for evaporated extracts. You don't need to go to Merck to get it though. You can get 99% isopropyl alcohol in may drug stores, in the rubbing alcohol section. They usually have both 70% and 99%. The 99% is more for use as an antiseptic than for massages. It's US pharmaceutical grade (USP) so very pure. The other 1% is just water. That's what I use myself.